Fuel systems of internal combustion engines are known from the marketplace, in which fuel systems the fuel is delivered from a fuel tank under high pressure by means of a mechanically driven piston fuel pump into a fuel rail and passes from there via injectors into combustion chambers of an internal combustion engine.
In the piston fuel pump which is known from DE 10 2004 063 074 A1, for example, a displaceably mounted pump piston is provided which compresses fuel in a delivery space of the piston fuel pump. The pump piston is guided in a piston bushing with a small sealing gap and such that it slides by way of a close fit. In order to support and seal via a gap seal, the piston bushing has to have a certain length and possibly absorb great transverse forces. Therefore, the piston bushing is often produced from steel. On account of high tolerance requirements, moreover, what is known as a “piston pairing” is used, that is to say each pump housing is assigned a defined piston. Furthermore, the cylinder in the pump housing has to be honed in a complicated manner. There is a requirement for a fuel piston pump which is less complicated to produce.